单缺位Dawson结构杂多钨酸盐绿色催化H_2O_2氧化环己酮合成己二酸

制备了单缺位Dawson结构杂多钨酸盐K10P2W17O61.13H2O催化剂,以H2O2为氧源,催化氧化环己酮合成了己二酸;采用FTIR和TG分析等方法表征了催化剂的结构与热性能;考察了催化剂的焙烧温度、催化剂用量、反应时间、H2O2用量、酸性助剂等因素对己二酸收率的影响,并考察了催化剂的重复使用性能。实验结果表明,该催化剂在100℃下焙烧2h后对H2O2氧化环己酮合成己二酸的反应具有良好的催化活性;合成己二酸的适宜反应条件为:环己酮用量100mmol、n(H2O2)∶n(环己酮)=4.45、催化剂用量(占环己酮的摩尔分数)1.5%、反应时间6.0h。在此条件下,己二酸收率为74.0%。使用该催化剂,在己二酸合成反应中无须添加有机溶剂、酸性助剂和相转移剂,有益于降低成本、简化分离工艺、减少污染和提高产品质量。

Green Catalytic Oxidation of Cyclohexanone with H2O2 to Adipic Acid Using a Monovacant Dawson Heteropolytungstate as Catalyst

A monovacant Dawson heteropolytungstate K10P2W17O61·13H2O catalyst was prepared and used in the oxidation of cyclohexanone with 30% hydrogen peroxide as oxidant to adipic acid. The catalysts calcinated at different temperatures were characterized by means of FTIR and TG. Effects of catalyst calcination temperature,catalyst dosage,reaction time,mole ratio of hydrogen peroxide to cyclohexanone and acidic additives on the oxidation were investigated. Reusability of the catalyst was studied. The appropriate preparation conditions for the heteropolytungstate K10P2W17O61 13H2O catalyst was calcination temperature 100 ℃ for 2 h. Under the optimal reaction conditions of cyclohexanone dosage 100 mmol,mole ratio of hydrogen peroxide to cyclohexanone 4.45,mole fraction of catalyst in cyclohexanone 1.5% and reaction time 6.0 h,yield of adipic acid could reach 74.0%. The oxidation reaction could be carried out without any organic solvents,acidic additives and phase transfer agents.